Surgical Access Device with Adjustable Cannula

ABSTRACT

A surgical access device is provided having a cannula and obturator. The cannula has a housing and tube section with an anchor located about the tube section. The obturator has a mechanism to deploy the anchor and adjust the cannula length. The anchor is moveable between a deployed and undeployed state where the undeployed state facilitates insertion and removal of the access device and the deployed state assists in fixation of the cannula in an anatomic structure. Anchor deployment is independent of cannula length adjustment.

BACKGROUND

The present invention relates in general to surgical devices andprocedures, and more particularly to minimally invasive surgery.

Surgical procedures are often used to treat and cure a wide range ofdiseases, conditions, and injuries. Surgery often requires access tointernal tissue through open surgical procedures or endoscopic surgicalprocedures. The term “endoscopic” refers to all types of minimallyinvasive surgical procedures including laparoscopic, arthroscopic,natural orifice intraluminal, and natural orifice transluminalprocedures. Endoscopic surgery has numerous advantages compared totraditional open surgical procedures, including reduced trauma, fasterrecovery, reduced risk of infection, and reduced scarring. Endoscopicsurgery is often performed with an insufflatory fluid present within thebody cavity, such as carbon dioxide or saline, to provide adequate spaceto perform the intended surgical procedures. The insufflated cavity isgenerally under pressure and is sometimes referred to as being in astate of pneumoperitoneum. Surgical access devices are often used tofacilitate surgical manipulation of internal tissue while maintainingpneumoperitoneum. For example, trocars are often used to provide a portthrough which endoscopic surgical instruments are passed. Trocarsgenerally have an instrument seal, which prevents the insufflatory fluidfrom escaping while an instrument is positioned in the trocar.Endoscopic surgery may also be performed in the absence of insufflatorygas. For example, minimally invasive thoracic surgery may be performedin the absence of insufflatory gas.

While surgical access devices are known, no one has previously made orused the surgical devices and methods in accordance with the presentinvention.

BRIEF DESCRIPTION OF DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim the invention, it is believed the inventionwill be better understood from the following description taken inconjunction with the accompanying drawings illustrating somenon-limiting examples of the invention. Unless otherwise indicated, thefigures are not necessarily drawn to scale, but rather to illustrate theprinciples of the invention.

FIG. 1 depicts is an isometric view of a surgical trocar having acannula and obturator with a cannula anchor in a deployed state;

FIG. 2 is an exploded view of the surgical trocar of FIG. 1;

FIG. 3 is an isometric view of the FIG. 1 trocar obturator;

FIG. 4 is a partial cross-sectional view of a surgical trocar having acannula anchor in a deployed state;

FIG. 5 is a partial cross-sectional view of a surgical trocar with acannula anchor in a deployed state and an obturator in an unarmed state;

FIG. 6 is a partial cross-sectional view of a surgical trocar with acannula anchor in an undeployed state and an obturator in an armedstate;

FIG. 7 is a partial cross-sectional view of a surgical trocar cannulahousing with an obturator inserted into the housing, further depictingrotation of the obturator to release the cannula anchor;

FIG. 8 is a partial cross sectional view of a cannula in a shortenedstate where the cannula anchor has deployed;

FIG. 9 depicts rotation of the cannula housing to change the length ofthe surgical trocar cannula;

FIG. 10 depicts threads or raised surfaces of the exterior cannula tubehousing contacting operative site tissue;

FIG. 11 is an isometric view of another expression of the surgicaltrocar access device depicting the cannula anchor in an undeployed stateand the obturator in an armed state;

FIG. 12 is an isometric view of a surgical trocar access deviceobturator having a two-piece tube with a threaded length adjustmentfeature;

FIG. 13 is a partial cross sectional view of the FIG. 12 trocar;

FIG. 14 is an exploded view of FIG. 13 obturator components;

FIG. 15 is a partial cross sectional view of the FIG. 14 components;

FIG. 16 is an isometric view of an obturator shaft for use with the FIG.11 trocar;

FIG. 17 is another expression of a surgical trocar access devicedepicting a surgical trocar cannula having a lower cannula with a ribbedsurface and further having cannula anchors in a fully deployed state;

FIG. 18 is a partial cross-sectional view of the FIG. 17 cannula;

FIG. 19 is a partial cross-sectional view of the obturator depicted inFIG. 16 inserted into the cannula depicted in FIG. 17 prior to insertioninto an operative site;

FIG. 20 is a close up of the cannula tube and obturator depicted in FIG.19;

FIG. 21 is a partial cross-sectional view of the FIG. 19 assembly withthe obturator shaft moved to the anchor deployment detent and thecannula anchors in a deployed state;

FIG. 22 is a close up view of the FIG. 21 anchor and distal end of theobturator;

FIG. 23 is a partial cross sectional view of the FIG. 11 surgical accessdevice with the anchor deployed and the cannula length reduced to itsshortest length;

FIG. 24 is a close up of the distal end of the FIG. 23 surgical accessdevice with the obturator shaft partially removed;

FIG. 25 depicts another expression of a trocar cannula length adjustingdevice;

FIGS. 26, 26A and 26B depict an exploded view of the FIG. 25 cannulahousing assembly for performing cannula length adjustment; and

FIGS. 27A, 27B, 27C, and 27D depict a mechanical deployment apparatusfor a trocar having an in vivo anchor assembly.

DETAILED DESCRIPTION

The devices and methods disclosed herein relate to providing access toan operative site and in particular to surgical trocar access devicesthat provide access to the abdomen and thoracic cavity. The trocarspermit insertion and removal of surgical instruments during an operativeprocedure and are particularly suited for minimally invasive surgicalprocedures. Expressions of a surgical trocar will be described in detailwith reference to drawings wherein like reference numerals designateidentical or corresponding elements in each of the several views.

For purpose of explanation and illustration and not limitation, anisometric view of one expression of a surgical trocar access device, ortrocar, is shown in FIG. 1 and is designated by reference number 100.Other expressions of surgical trocars are presented in FIGS. 2-34, aswill be described fully herein.

Referring to FIG. 1, trocar 100 is comprised of a cannula 110 and anobturator 120 inserted in cannula 110. In one expression of the trocar100, the cannula is comprised of two cannula tubes, 130 and 140. Distalcannula tube 130 is adapted to receive proximal cannula tube 140. In oneexpression of the trocar 100, distal cannula tube 130 may be flexibleand include impressed threads 160. Proximal cannula tube 140, in oneexpression, is generally rigid in its construction and may furtherinclude threads 150 which may be adapted to mate with impressed threads160. Trocar 100 also includes a distal anchor 170 which assists inanchoring cannula 110 in an abdominal wall or any other suitableanatomy.

Referring now to FIG. 2, trocar obturator 120 is provided to facilitateinsertion of cannula 110 into an appropriate anatomic structure.Obturator 120 is provided with an anchor deployment button 210.Obturator 120 includes finger grip area 220 to facilitate insertion andremoval of obturator 120 from cannula 110. Obturator 120 furtherincludes obturator tube 260 and may further include distal anti-rotationlocks 230A and 230B and anchor deployment shaft 240. Anti-rotation locks230A and 230B, extend distally from a distal end of obturator 120 in acantilevered manner and may be disposed about the medial surface of tube260. In one expression, locks 230A and 230B have a triangular shapeterminating in a peak. Locks 230A and 230B are in mechanicalcommunication with openings 340A and 340B in distal cannula tube 130,and may be spring-biased to facilitate insertion into cannula 110.Obturator 120 may further include a tip 250 to facilitate insertion ofthe trocar 100 into an anatomic structure. Tip 250 may comprise a flatblade, pyramidal blade, an optical dilation tip, blunt tip or the like.Obturator 120 may be adapted to accommodate an endoscopic camera system,as in known in the art.

Cannula 110 is provided with a seal 320 which may be located in cannulahousing 310, as seen in FIG. 3. Seal 320 may be comprised of a duckbillvalve and an elastomeric annular seal as shown in FIG. 3. Seal 320 maybe provided with a flapper valve in place of the duckbill or may beprovided with only an elastomeric annular seal, or any combinationthereof, as is known in the art or any other seal to prevent the escapeof insufflations gas. Seal 320 may be sized to accommodate variousdiameter surgical instruments e.g. 3 mm to 12 mm.

Cannula housing 310 is generally cylindrical and sized to provide agripping surface for insertion of trocar 100 into an anatomic structure.Housing 310 is also sized to contact the exterior surface of an anatomicstructure and is larger than an incision through which the cannula tube130, 140 is passed. Housing 310, in the present expression, iscylindrical in nature but may be any shape or size such that it can begripped and will not pass into an incision. Cannula housing 310 andcannula tubes 130, 140 are hollow in nature and define a lumen 330.Lumen 330 is sized to permit the passage of surgical instruments and mayaccommodate surgical instruments of different diameters e.g. 3 mm to 12mm. Extending distally from cannula housing 310, cannula tube 140contains threads 150 which are designed to mate with impressed threads160 on distal cannula tube 140. Cannula tube 140 is further providedwith openings 340A and 340B (not pictured) to mate with distalanti-rotation locks 230A and 230B.

Distal cannula 130 further comprises cannula anchor 170, locatedadjacent the distal end of cannula tube 130, but may be located anywherealong cannula tube 130. Anchor 170 is, in one expression, formed ofpliable elastomer and may be deformed longitudinally.

Referring now to FIG. 4, an exploded view of trocar 100 is provided.Anchor deployment assembly 400 of obturator 120 is arranged with anchorlocks 410A and 410B disposed about anchor shaft 240. Anchor spring 430is further disposed about anchor shaft 450 and may move freely betweenlocks 410 and tip 250. Anchor deployment button 210 defines the proximalend of anchor deployment shaft 450. Tip 250 defines the distal end ofshaft 450 and may be removably attached to shaft 450 to permitattachment of different trocar tips. Anchor locks 410A and 410B, in oneexpression, extend distally from ring 405 in a proximal-to-distalcantilevered manner along shaft 450 defining a gap such that the anchorsare medially resiliently deflectable and may further have chamfereddistal surfaces to facilitate insertion into obturator 120 and cannulahousing 310. Anchor lock slots 420A and 420B are dimensioned toaccommodate anchor locks 410A and 410B and permit rotational forcetransfer from housing 220 to anchor locks 410A and 410B. Anchordeployment assembly further comprises an anchor shaft cap 440 thatdefines a medial annulus 460 dimensioned to mate with button 210 suchthat button 210 protrudes from a proximal side of cap 440.

FIG. 5 is a partial cross sectional view of trocar 100 in an unarmedstate. Anchor deployment assembly 400 is inserted through obturator 120and obturator 120 is inserted into cannula 110 forming trocar 100.Angled surface of anchor locks 230 creates medial deflection of locks230 upon insertion into cannula 110. When locks engage openings 340,peak of locks 230 protrudes into opening permitting the transfer ofrotational force from the obturator 120 to cannula tube 130 creating aspline-groove type engagement.

A flange portion of tip 250 may engage anchor 170 when obturator 120 isinserted, permitting tip 250 to extend a predetermined distance beyondanchor 170. As shown, tip 250 engages anchor 170 as obturator housing220 abuts cannula housing 310. Cannula housing 310 is provided with atleast two anchor deployment detents 510A and 510B to receive and holdlocks 410A and 410B. Detents 510A and 510B may be disposed in an annularfashion along the medial surface of cannula housing 310 and, in oneexpression, span less than 90° each. In an unarmed state, anchor locks410A and 410B are disposed above detents 510A and 510B such thatobturator 120 is axially slideable with respect to cannula 110. Spring430 may be axially slideable along anchor tube 240 between ring 405 andcannula flange 520 when trocar 100 is unarmed. Locks 230A and 230Bengage cannula openings 340A and 340B and slide axially within openings340A and 340B, permitting obturator 120 to move axially while locks 230are engaged with openings 340.

When anchor deployment button 210 is depressed, anchor deployment shaft400 moves in a distal longitudinal direction relative to obturator 120and cannula 110. As button 210 is depressed, lateral flange of tip 250engages medial flange of anchor 170 thereby transferring force frombutton 210 axially to anchor 170. Anchor 170 extends distally andcollapses into the approximate diameter of cannula tube 130 as shown inFIG. 6. In one expression of trocar 100, when anchor 170 is elongatedsuch that its diameter is appropriate for insertion through an incision,chamfered surfaces of anchor locks 410A and 410B medially deflect locks410A and 410B against detents 510A and 510B until 410A and 410B areseated below detents 510A and 510B creating an interference fit andpreventing distal axial motion of obturator 120 relative to cannula 110.Openings 340A and 340B are dimensioned such that rotation locks 230A and230B remain engaged with openings 340A and 340B as obturator 120 ismoved in a distal axial direction from an unarmed to an armed state. Inan armed state, spring 430 is compressed between ring 405 and detents510A and 510B, creating a proximal axial force on anchor deploymentassembly 400 relative to obturator 120.

FIG. 7 is a partial cross sectional view of the proximal portion oftrocar 100 in an armed state. As described previously, anchor locks 410Aand 410B seat below detents 510A and 510B preventing distal axial motionof obturator 120 relative to cannula 110. As depicted in FIG. 7, cannulahousing 310 is provided with detents 510 and detent openings 710A and710B. After trocar 100 is inserted through an incision into an anatomicstructure in an armed state, it is necessary to deploy anchor 170 toprovide fixation in the anatomic structure.

By rotating obturator housing 120, anchor locks 410A and 410B align withdetent openings 710A and 710B; force from spring 430 exerts proximalaxial force on ring 405 and moves anchor deployment shaft 400 in aproximal direction away from anchor 170, relieving tension on anchor 170allowing anchor 170 to resume a deployed shape as depicted in FIG. 1.Button 210 returns to an unarmed position as depicted in FIG. 5 andtrocar 100 is once again in a unarmed state. In this state, shouldobturator tip 250 be pressed axially against an anatomical structure,there is no concomitant force to counteract the movement of anchor 400from moving in a manner away from the anatomic structure.

Once trocar 100 is inserted into an anatomic structure and disarmed, itmay be desirable to shorten the length of cannula 100. By rotatingobturator housing 220 in a counterclockwise manner (depending upon theorientation of threads 150 and 160) while holding cannula housing 310stationary, rotational force is transferred from housing 220 throughlocks 230A and 230B to distal cannula openings 340A and 340B therebyrotating distal cannula 130 in a counterclockwise manner. Obturator 220may be held stationary while housing 310 is rotated, as shown in FIG. 9.Threads 160 engage proximal cannula threads 150 and drive distal cannula130 proximally over proximal cannula 140, thereby shortening the in vivolength of cannula 110. Once a desired in vivo length is achieved,obturator 120 is removed from cannula 110 permitting insertion andremoval of surgical instruments. Anchor 170 provides axial resistance toremoval of cannula 110 by contacting the inner surface of an anatomicstructure when proximal axial force is applied to cannula 110. Threads150 and 160 contact the anatomic structure wall 1010 (e.g. abdominalwall) as shown in FIG. 10, further providing resistance to proximal anddistal motion of cannula 110 as instruments are inserted and removedfrom cannula 110.

Referring now to FIG. 11, another expression of a surgical trocar 1100is depicted. As shown, anchor 1170 is under tension in a collapsedstate. In this position, obturator shaft 1110 is fully extended throughcannula 1105 and trocar 1100 is in an armed state, ready for insertionthrough an incision into an anatomic structure. Cannula 1105 iscomprised of two cannula tubes, proximal tube 1160 and distal tube 1180to which anchor 1170 is attached. Anchor 1170 may be formed from tube1180 thereby creating a contiguous tube-anchor structure. Obturatorhousing 1115, in one expression, is formed from three interleavedcylindrical housings 1120, 1130 and 1140, which are more fully depictedin FIG. 12.

FIG. 12 illustrates obturator housing 1115 with proximal obturator tube1210 attached thereto. In one expression of the instant surgical accessdevice, tube 1210 is provided with a threaded surface designed to matewith a threaded interior on distal obturator tube 1220 (see FIG. 13 tube1220). When housing 1115 is rotated, tube 1210 is concomitantly rotateddriving tube 1210 into distal tube 1220 when tube 1220 is heldstationary relative to tube's 1210 rotation. Tube 1220 is provided withlocking fingers 1230 at its distal end to engage obturator shaft 1110when inserted into obturator housing 1115. Radial locks 1235 are formedon a lateral surface of fingers 1230 to engage anchor 1170 and distalcannula tube 1180. Obturator housing 1115 is provided with a base 1250to receive housing 1140. Base 1250 defines a medial opening 1240 whichmay be adapted to receive cannula 1105 housing therein.

Partial cross sectional view of obturator housing 1115 in FIG. 13depicts the interleaved nature of cylindrical housings 1120, 1130 and1140. Cylindrical housings 1120, 1130, 1140 engage and may press fitonto obturator housing base 1250 to form a contiguous surface. Proximalaxial force exerted on proximal-most housing 1120 in turn exerts axialforce on housing 1130 which, in turn, exerts axial force on housing 1140facilitating removal of obturator 1115 from cannula. Housing 1115further contains obturator shaft detent pin 1310 which engages detentson obturator shaft 1110.

Referring now to FIGS. 14 and 15, housing 1130, in one expression, isprovided with a toothed distal medial surface 1410. When housing 1115 isassembled, toothed surface 1410 engages pawls 1420A, 1420B, 1420C. Whenhousing 1130 is rotated, pawls 1420 permit rotation in a singledirection creating a slip clutch arrangement. Rotation of housing 1130in turn rotates housing 1120 which in turn rotates proximal obturatortube 1210.

Obturator 1115 is provided with obturator shaft 1110 as shown in FIG.16. Shaft 1110 is provided with a gripping surface 1610 and detents 1620and 1630. The distal end of shaft 1110 is provided with leaf springanchor extension fingers 1640A and 1640B adapted to engage a medialflange portion of anchor 1170. Shaft tip 1650 is provided at the distalend of shaft 1110 and may be an optical tip, a bladed tip, a blunt tipor any other tip known in the art.

FIG. 17 illustrates cannula 1105 of trocar 1100. In one expression oftrocar 1100, cannula 1105 is comprised of a housing 1720, a proximalcannula tube 1160, a distal cannula tube 1180 located adjacent tube 1160and an anchor 1170 which may be located at a distal end of tube 1180.Anchor 1170, in one expression, is provided with proximal ring 1730 anddistal ring 1720 and living hinges 1740. Living hinges 1740 may bebiased to an open position as shown in FIG. 17. Distal ring 1720includes a medial annular flange adapted to engage fingers 1640A and1640B of obturator shaft 1110 to facilitate collapsing the anchor 1170for insertion into an anatomic structure. As depicted in FIG. 17, distaltube 1180 is provided with a corrugated surface which may reducefriction forces during cannula tube 1180 retraction into cannula tube1160. When cannula tube 1180 is retracted into tube 1160, tube 1180 isheld in place through an interference fit provided by the reducedproximal diameter of tube 1160, as is shown in FIG. 18. Housing 1710 maybe provided with a sealing system 1820 and 1830 to prevent the escape ofinsufflatory gas where the seal 1820 is a duckbill valve and 1830 is adiaphragm seal. Any form of seal may be used to prevent the escape ofinsufflatory gas, as is known and understood in the art. Cannula 1105 isprovided with chamfered opening 1830 to facilitate insertion ofobturator shaft 1110 as well as surgical instruments.

FIG. 19 depicts a partial cross sectional view of trocar 1100 withobturator shaft 1110 inserted through obturator housing 1115 andobturator shaft detent 1620 engaged with detent pin 1230. In thisposition, anchor extension fingers 1640A and 1640B engage anchor ring1720 (see FIG. 20) and push anchor 1170 distally collapsing anchor 1170about tube 1180. In this position, trocar 1100 is armed for insertioninto an anatomic structure. Referring to FIG. 20, obturator shaft 1110engages distal tube locking fingers 1230 biasing fingers 1230 laterally.In this biased position, locking fingers 1230 radial teeth 1235 engageanchor proximal ring 1730 permitting axial force transfer from obturatorshaft 1110 to cannula distal tube 1180.

Once inserted into an anatomic structure, it may be desirable to deployanchor 1170 as shown in FIGS. 21 and 22. Applying proximal axial forceon obturator shaft 1110 moves shaft 1110 detent 1620 out of engagementwith pin 1230 and into engagement with detent 1630. This movementremoves fingers 1640A and 1640B from engagement with anchor ring 1720permitting anchor 1170 to bias to a deployed state. In this state,anchor 1170 may engage the interior wall of an anatomic structure,preventing inadvertent removal of cannula 1105 during surgicalinstrument exchanges.

It may be desirable to reduce the overall length of cannula 1105.Cannula 1105 length change may be accomplished in vivo or ex vivo, withthe anchor 1170 in a collapsed state or deployed state. With obturatorshaft 1110 inserted into obturator housing 1115 such that shaft detents1620 or 1630 engage pin 1230, shaft 1110 engages locking fingers 1230such that shaft 1110 and tube 1220 create an interlocking fit, or maycouple in a locking fashion, and pin 1230 and detents 1620 or 1630create an interference fit. This interference fit permits transfer offorce from housing 1120 to shaft 1220. Similarly, engagement of toothedsurface 1410 and pawls 1420A, 1420B, and 1420C permits the transfer offorce (e.g. rotational force) applied to housing 1130 to tube 1210. Whenhousing 1130 is rotated and housing 1120 is held in a stationaryposition, threads on lateral surface of tube 1210 engage threads onmedial surface of 1220, rotating tube 1210 and thereby driving tube 1220in a proximal direction. Radial teeth 1235 engage anchor ring 1730transferring proximal axial force from tube 1220 to cannula tube 1180thereby moving cannula tube 1180 in a proximal direction into tube 1160,shortening the length of cannula 1105. Cannula tube 1180 is held inposition due to the friction between tube 1160 and 1180, as statedpreviously. Once a desired length is achieved, obturator shaft 1110 isremoved as shown in FIG. 23.

Upon shaft 1110 removal, locking fingers 1230 return to a mediallybiased position as shown in FIG. 24. In this position, radial teeth 1235disengage from ring 1730 permitting removal of obturator 1115 fromcannula 1105. As shown in FIGS. 23 and 24, cannula tube 1180 is fullywithdrawn into tube 1160. It is understood that tube 1180 may bewithdrawn partially into tube 1160 as well.

Referring now to FIG. 25, another expression of a surgical trocar isdepicted. Trocar 2500 includes a collapsible segment 2510 which may beuseful in making preliminary adjustments to overall cannula 2505 length.Segment 2510 is located adjacent cannula tube 2515 and cannula housing2520. Before inserting a trocar into an anatomic structure, it may bedesirable to approximate cannula length which may reduce time taken toadjust cannula length in vivo. As depicted in FIG. 25, preliminaryadjustment may be achieved by an accordion section 2510 which may becomprised of an elastomer and be flexible in nature, or may be rigid,depending upon application and need.

One expression of collapsible segment 2510 adjustment mechanism depictedin FIG. 25 is shown in FIGS. 26, 26A and 26B. Tension members 2620A and2620B are affixed to cannula tube 2515 at tension members 2620A and2620B distal ends. Proximal ends of members 2620A and 2620B are affixedto spool 2630. Spool 2630 includes a keyseat 2640 adapted to receiveobturator 2650 key 2655. Rotation of obturator 1650 transfers rotationalforce through key 2655 to keyseat 2640 thereby turning spool 2630 andwinding tension members 2620A and 2620B around spool 2640. This windingshortens tension members 2620A and 2620B collapsing section 2510. Asdepicted in FIG. 26, section 2510 is an accordion type housing havinglateral and medial surfaces with tension members 2620A and 2620B locatedin a plane between lateral and medial section 2510 segments. Members2620A and 2620B may be located on a medial surface or a lateral surfacedepending upon application and need.

Cannula housing 2520 lateral surface, in one expression, is providedwith a lock 2660 adapted to hold spool 2630 in a fixed position relativeto housing 2520. Lock 2660 may be a camming lock where annular movementdrives a portion of lock medially onto a lateral surface of spool 2630holding spool 2630 and housing 2520 stationary relative to each other.

Referring now to FIGS. 27A, 27B, 27C and 27D, a trocar insertion handle2700 is provided. Handle 2700 is adapted to receive a surgical trocar2740. Handle 2700 is further provided with an obturator 2720. Obturator2720 is adapted to receive and engage cannula 2740. Anchor deploymentbutton 2710 is provided at a proximal end of obturator 2720 and isadapted to cooperate with anchor 2770 located at cannula 2740 distalend. When button 2720 is depressed distally, spring 2730 is collapsedbetween button 2710 and handle housing 2705, anchor 2770 is moveddistally, collapsing anchor 2770 around cannula 2740 placing trocar 2740in an armed state, ready for insertion into an anatomic structure.Obturator 2720 is provided with a detent in communication with button2775 to hold anchor 2770 in a collapsed state (not shown). Obturator2720 may be provided with a tip 2750 suitable for insertion through ananatomic structure (e.g. abdominal wall, etc.).

After insertion of trocar 2740 into an anatomic structure as shown inFIG. 27B, it may be desirable to deploy anchor 2770. Button 2775 isdepressed allowing spring 2730 to bias obturator 2720 proximally,permitting anchor 2770 to assume a deployed state. Depending upon thecomposition of anchor 2770, it may be necessary to pull obturator button2710 proximally to deploy anchor 2770. Once anchor 2770 is deployed,handle 2700 may be removed as shown in FIG. 27D. As shown, handle 2700and obturator 2720 are of unitary construction. It is contemplated thathandle 2700 and obturator 2720 may comprise two or more separatecomponents. Upon removal of handle 2700, cannula 2740 may be shortenedto an appropriate length. It is also contemplated that handle 2700 mayfurther comprise a cannula adjustment mechanism such that cannulaadjustment is accomplished with handle 2700 attached to cannula 2740.

Having shown and described various embodiments and examples of thepresent invention, further adaptations of the methods and devicesdescribed herein can be accomplished by appropriate modifications by oneof ordinary skill in the art without departing from the scope of thepresent invention. Several of such potential modifications have beenmentioned, and others will be apparent to those skilled in the art. Forinstance, the specific materials, dimensions, and the scale of drawingswill be understood to be non-limiting examples. Accordingly, the scopeof the present invention should be considered in terms of the followingclaims and is understood not to be limited to the details of structure,materials, or acts shown and described in the specification anddrawings.

1. A surgical trocar comprising: a) a cannula having a housing; b) acannula tube; c) a collapsible segment disposed between the housing andthe tube; d) a spool located within the housing; and b) a tension memberin communication with the spool and the cannula tube wherein rotation ofthe spool causes the tension member to shorten thereby moving thecannula tube toward the cannula housing and collapsing the collapsiblesegment.
 2. The surgical trocar of claim 1, wherein the collapsiblesegment is comprised of a lateral segment and medial segment.
 3. Thesurgical trocar of claim 2, wherein the tension member is locatedbetween the lateral and medial segments.
 4. The surgical trocar of claim3, wherein the collapsible segment is flexible.
 5. The surgical trocarof claim 4, wherein the cannula tube is rigid.
 6. The surgical trocar ofclaim 5, further comprising a lock in communication with the spool. 7.The surgical trocar of claim 6, further comprising an obturator locatedmedial to the housing, the collapsible segment and the cannula tube. 8.The surgical trocar of claim 7, further comprising a tissue piercing tipat the distal end of the obturator.
 9. The surgical trocar of claim 7,further comprising a valve located within the cannula housing.
 10. Asurgical trocar comprising: a) a cannula having a housing; b) a rigidcannula tube; c) a flexible collapsible segment disposed between thehousing and the tube, the collapsible segment rotatably attached to thehousing; d) a spool located within the housing; e) a lock attached tothe housing in disengageable communication with the spool; and b) atension member in communication with the spool and the cannula tubewherein engagement of the lock and rotation of the housing causesrotation of the spool thereby causing the tension member to shortenthereby moving the cannula tube toward the cannula housing andcollapsing the collapsible segment.
 11. The surgical trocar of claim 10,wherein the spool is arranged substantially perpendicular to the cannulatube, the spool having a medial annulus of a diameter to accommodatepassage of surgical instruments therethrough.
 12. The surgical trocar ofclaim 11, further comprising a valve located substantially within thehousing.
 13. The surgical trocar of claim 11, wherein the lock is a camlock.
 14. The surgical trocar of claim 13, wherein the collapsiblesegment is comprised of a lateral segment and medial segment.
 15. Thesurgical trocar of claim 14, wherein the tension member is locatedbetween the lateral and medial segments.
 16. A surgical trocarcomprising: a) a cannula having a housing; b) a cannula tube; c) acollapsible segment disposed between the housing and the tube; d) aspool located within the housing, the spool having a medial annulus; anopening in the medial annulus defining a keyseat; and e) a tensionmember in communication with the spool and the cannula tube.
 17. Thesurgical access device of claim 16, further comprising an obturatorhaving a key to engage the keyseat.
 18. The surgical trocar of claim 17,wherein the collapsible segment is comprised of a lateral segment andmedial segment.
 19. The surgical trocar of claim 18, wherein the tensionmember is located between the lateral and medial segments.
 20. Thesurgical trocar of claim 16, wherein the collapsible segment isflexible.